Hardness-tester.



H. M. & S. P. ROCKWELL.

HARDNESS TESTER- APPLICATION FILED JULY 15,1914.

Patented Feb. 11,1919.

All

- NPR! l 1 m mm INVENTORS I: Mac/(Well 19 P. flockwefi' B 5 ziTTORNEYi9? WITNESSES;

, Y HARDNESS-TESTER.

Specification of Letters Patent.

Patented lFel'o. llli, 1919.

Application filed July 15,1914. Serial No. 851,106.

To all whom it may concern:

Be it known that we, Hoot; M. ROCKWELL and STANLEY P. ROCKWELL, citizensof the United States, residing at Bristol, county of Hartford, State ofConnecticut, have invented a certain new and useful Hardnesslester, ofwhich the following is a full, clear, and exact description, such aswill enable others skilled in the art to which it appertains to make anduse the same, reference being had to the accompanying drawings,forming-part of this specification.

Our invention relates to testing machines, andmore particularly tohardness testers.

In the manufacture of the cups and cones of antifriction bearings, it ishighly desirable to test the hardness of the cups and cones andespecially thehardness of their curved raceways. Previous hardness testers, when attempts have been made to apply them to this kind of testing,have been found open to various objections. "For example, machines whichrequire that the test be made upon a flat surface are not applicable tothe testing of the curved raceways, and even such machines are, when ofa type to give tests of suflicient accuracy on the flat surfaces towhich they are restricted, too complicated and require too greatmanipulative skill to be used successfully-by the ordinary shop workman,and also are too slow in operation 'to be used in testing large numbersofarticles in the time which can, commercially, be devoted to suchtesting, while devices, as'a file, which can be used for curved surfacetesting are not sufficiently accurate. V e have devised a hardnesstester which can be used by the ordinary workman to rapidly andaccurately test the hardness not only of flat surfaces but also ofraceways and other curved surfaced bodies.

One object of our invention is to provide a hardness tester which can beused in testmg curved surfaced bodies at and below the curved surface.

Another object is to provide a tester which Another ob ect s to providea device of the character above indicated which can'be rapidly operated,is'simple in construction,

canbe inexpensively manufactured, and will give accurate results, v a

To these endsand also to Improve generally -upon devices of thecharacter indicated,

ing lever and an actuating means therefor;

and

Fig. 5 is a fragmental perspective vie-w showing the clamping mechanismfor holding the resistance abutment and the table block in position. v

Without restricting our invention thereto, we show and describe a devicemore particularly adapted for the testing of the hardness of steel cupsand cones. w

' The illustrated tester comprises a testing device shown as apenetrator. or point 1, fixed against movement, and a force applyingelement or plunger 2, mounted for movement to and .from the point 1. Theplunger 2 is operatively' connected with the short arm 3 of a lever,designated generally as 4:, to move the lever. The lever 4 is fulcrumedat 5 and has its long arm 6 in contact with the plunger 7 of the dialindicator 8. As is common in dial indicators, the plunger 7 is" alwaysurged toward its outermost position by suitable mechanism within theinstrument. I

'With the construction thus far described,

it will be seen that if pressure be applied to the plunger 2 suchplunger will force an article, as the cup 9, against the point land, asthe point 1 penetrates the cup, the extent of movement will be indicatedby the pointer 10.

A lever, designated generally as 11, is fulcrumed at 1'2 and has itsshort arm '13 (which for 'antiifrictional purposes/may include a roller14) so operatively connected withthe plunger 2, by the cam block 15hereinafter more fully referred to, that a load of agiven amount (saypounds X inches) ap lied to the long arm. 16 of the lever 11, in t evarious angular positions ofthe lever, will always result-in thesamelongitudinal pressure being applied to theplunger 2.

The long arm 16 of-the lever 11 is composed of two L-shaped sections 17and 18, respectively, hinged together by the pm 19.

.A load applying device is connected to the stem or abutment 18 of thesection 18. Thls device preferably comprises a line or wire 20 whichpasses loosely through the stem or abutment 17 of the section 17, over apulley 21, (carried by and with the section 17), loosely .throu h thefulcrum point 12 of the lever 11, and is loaded with a hanging weight22. This load applying device holds, within limits, the stem or abutment18 in fixed relation with respect to the coeperating abutment 17 and somaintains the lever arm rigid at thehinge.

With the construction just above described, it will be seen that, if aload be.

applied to the long arm 16 which load is, by the slightest amount,greater than the pull of the weight 22, the section 18 will hinge aboutthe' point 19 and only the load determined by the pull of theweight willbe effectively applied. Thus no load greater than the pull of the weight22 can be efiectively exerted on the long arm of the lever. Inconsequence, no force greater than a predetermined one can be exerted bythe lever on the plunger.

We find this construction very des rable, as, with it, it will be seenthat it is only necessary to instruct the Workman, to in a test, applysufiicient power to buckle the lever at the hinge. If he follows theseinstructions it is clear that he will alwaysapply a fixed force or loadto the plunger.

In use, the article to be tested, as the cup 9, is placed in positionand the plunger brought easily against it to firmly center it and theinitial reading of the pointer 10 taken, as by turning the dial to bringthe zero of the scale beneath the pointer. Pres; surejis then applied tothe lever 11 'until it buckles at the hinge 19. Pressure on the lever isthen relieved and the lever brought to such a position as to merelyfirmly bring the plunger against the work to thereby merely firmly butfully seatthe penetrator in the depression just made, and the finalreading of the pointer 10 taken.

Clearly the difi'erence between the. initial and the final reading givesthe permanent set depth of the depression made bythe penetrator and thisdepth'gives a definite indication as to the hardness of the testpiece,'the less the depth the harder the piece. Y

While, if desired, the total penetration of the penetrator could, ofcourse, be read from the dial we prefer the method of taking thepermanent set'read ing. This is because the total inwardmovement iscomposed of two factors, to wit: the inward movement due to theelasticity of the material beingtested and the inward movement due tothe rial being tested, and of a means for measuring the depths ofpenetration, the tests are not confined to test pieces having flatsurfaces, but that testpieces having arcuate surfaces, such as thesurface of the raceway of a-cup or cone, can be properly tested at andbelow the curved'surface.

It will also be seen that, with an indicator, as for example the dialindicator 8, connected for actuation during the operation of themachine, the results of the tests can be quickly and directly read olfbythe operator. Thus heis not under the necessity,

such as arises even in the use of certain fiat surface testers, ofremoving the test piece from the machine and manually measuring thedesired dimension which gives an indication as to hardness. And it willbe under.- stood that the various mechanisms, such, for example, as thatfor insuring the application of a fixed maximum load, are by no meansrestricted to use with indicating devices gi'ving the depth ofpenetration as they might also be combined with indicating means givingany suitable dimension of a depression. It will also be seen that by theuse of an automatic safety device, illustrated by way of example as thehinge 19, weight 22, etc., we provide that the device, can be properlyused by an unskilled operator.

The operative connection, -or transmitting and compensating means,betwfeen the lever J 11 and the plunger 2, for insuring that a load of agiven amount applied to the lever,

in the various angular positions of the lever, will always result in thesame longitudinal pressure on the plunger, ma y be of any suitablecharacter. Preferably, and as here shown, it comprises thebeforereferred to compensator or pivoted cam block 15. The camblock 15 has aportion in contact with theend of the plunger-2 and a cam surface 23 incontact with the lever. 'The cam surface '23 is, asillustrated, of sucha character that, assuming any given load applied to the lever, themoment arm as (1,,from the fulcrum 24 to the point of contact, as b, of

the end 'of' the lever with the cam surface so varies inlength,.as thelever 11. is moved, as to compensate for any changes in the size of theresultant force applied by the lever at,ri'ght angles to the arm .a' andunder the given load; to compensate for any changes in the length of themoment arm, as c, from the fulcrum 24 to the contact point as d, of theplunger with the cam block, and also to compensate for any changes inthe angle which the force acting'parallel with the axis of the plungermakes with the moment arm, as 0. Although the illustrated cam surfacecompensates for all these variations, it will be understood that itmight be designed to compensate for any suitable number of them, and toperform such compensation more or less accurately, depending upon theaccuracy of results desired in the tests for which the device is to beused. v Although in the present instance the portion of the lever incontact with the cam surface is shown as a roller, it will be underwiently reverse the position of the point 1.

; of the plunger 2, preferably at the same time using a resistanceabutment 2 6 I with a curved outer circumference to abut the innerperiphery of the cone.

- The work, as the cup 9, may be properly located in the machine in anysuitable man.- ner. As here illustrated,the base 27 is provided withparallel guides or supports 28, 28, which carry a table block, as 29.The block is shown, more particularly in Fig. 5,

as slidably connected with the guides by a,

tongue-and-groove-joint, preferably a dovetail joint. To provide fordiiferent heights (as the articles lie in a horizontal tester) of cupsand cones, for example, we may, of course, use table blocks of differentthicknesses, each table block'being of a suitable thickness to support arespective piece of work in proper relation to the penetrator andplunger. The table block 29 is shown as removable from the guideways inorder to provide for the substitution *of a block of differentthickness. member, for example, a table block may desirably be of athickness to brin the center line of a raceway substantially in linewith the penetrator. Y

' Conveniently, we may provide a table block, as 29, with asupplementary table plate 30 vertically adjustable with respect to thetable block proper. This vertical adjustment may be accomplished byadjusting screws 30 carried by the plate and rotatable butnon-longitudinally shiftalole, with re- In the case of a race,

blocks of various thicknesses, as might other-- wise be necessary.

In order to provide for the insertion of pieces of various thicknesses(longitudinally vof the instrument) the abutment 26 may be rigidlymounted upon a longitudinally shift able upper Wedge block 31 restingupon a lower wedge block 32. Both Wedge blocks are received between'theguides 28, 28, and below the table block 29 and the table block isprovided with an aperture 33 for the loose passage of the resistanceabutment 2,6.

A screw 34, conveniently carrying a hand wheel 35 fixed thereon, isrotatably carried in the journal 36 but is held against longitudinalmovement with respect thereto as shown. The screw 34 is screw-threadedinto the lower wedge block 32. With this construction the wedge blocksmay be manually so placed as to properly locate the abutment 26 and thenthe screw may be turned to force the inclined planes intimately intocontact with each other thereby forcing the upper wedge block againstthe lower side of the table block 29 and jamming the dovetail jointconnection, the block 29 serving as a resistance piece for the block 31.Thus the resistance abutment and the table block are locked in fixedposition bothwith respect to each other and to the frame of the machine;

It-will be understood, of course, that, although the above means areprovided whereby the abutment may be placed in various positions andlarge and small variations in thickness provided for, small variationsmay be provided for merely by placing the plunger in various initialpositions with respect to the abutment. This is because, due to thecompensating means, the angle at which the lever 11 stands makes nodifference in the amount of the force which willbe applied to theplunger.

Preferably the plunger2 is surrounded by a spring 37 under compressionand abutting, at one end. the support 38 and, at the other end, anadjustable collar 39 fixed in adjusted position on the plunger 2 by theset screw 39?. This spring acts to overcome any backlash in themechanism and to automatically withdraw the. plunger from the test piecewhen the plunger is relieved from pressure. It will be understood, ofcourse, that the spring is of such a character and the range V ofmovement of the plunger so'small, comparatively, that whatever changesthere might be in the force exerted by the spring in the variouspositions of the plunger would be so small as to be entirely negligible.

Theplunger 2 is shown as conveniently mounted in the support 38 and in asupport 40 for longitudinal travel therein. Inorder to connect theplunger with the short arm 3 trator 1 when'it is desired to test conesfor v'ided for" connecting the lever'with a foot-l example. I

As illustrated, the lever 4 is fulcrumed between the arms 44, 44, of thesupport 38 by means of the socketed adjusting screws 5, 45,respectively, carrying balls 46, 46, resting in sockets 47, 47, in thelever 4, the screws being held in adjusted position by the set screws48, 48. If desired an arm 44 may carry stop screws 49, 49, for the leverA. spring, as, 50, for maintaining the short arm of the lever in contactwith the collar 41 may be provided. Such spring is.

shown as carried by. the rod 51 adjustably mounted in the support 38 andheld in adjusted position by the setv screw 52.

The indicating means here, by way of example, illustrated as the dialindicator 8 maybe of any suitable character and may be supported in anysuitable manner. As illustrated the indicator 8 is carried by a support53 bolted to the base 27 and carrying the indicator adj ustablyconnected to its upper end as indicated generally at 54.

The pivot pin 24 of the cam block 15 is shown as mounted between thesides 55 of the support56. The lever 11 is shown as also fulcrumed, bythe pin 12, between these same sides, such pin being preferably fittedto move with the lever and having an aperture 57 therein for the passageof the before referred to wire 20. The aperture 57 is, as illustrated,of sufficient cross-section and such contour as to obviate.objectionable binding of the wire. The lever is shown as provided with acorresponding aperture 58 for the passage of the wire. 1

Preferably the wire 20 is connected to the stem of the section 18 by theset screw 59 :and passes loosely through an aperture 60 in the stem 17.

A link, as '61 (see Fig. ,4), or any other suitable connection, may ifdesired be pro- .treadle or other suitable device (not shown) forapplying-power to the lever, should it for any reason be desired 1 tonot use mere manual operation. An adjustable abutment for the lever11,.as the screw 62 may be provi-ded. I

A second indicator pointer 63 adapted to be manually set invario'uspositions with' respect to the primary pointer 10 and then to movetherewith may be provided, This pointer 63' may be set'a distance behindthe pointer 10 equal to the number of units representing the greatestsoftness permissible in the-test piece; Evidently with this ar measurethe depressions madeby the point 1 in thousandths of an inch, the actualdis-' tances being multiplied by the five-to-one lever 4, whereby fivegraduations of the dial indicator represent one one-thousandth of aninch depression, the indicator being a thousandths indicator. We havealso found it desirable to use such a weight 22 (as seventy-five pounds)and such a ratio between the lengths of the stem 18 and the short arm ofthe lever 11, as measured from the fulcrum 12 to the contact point I) ofthe roller (as 4:2) that the pressure exerted by the lever at the camblock shall be about one hundred and fifty pounds.

In raceway testing we prefer to apply the tests just before the finalgrinding operation as by so doing the permanent depressions are made inthe grinding allowance only so that, after final grinding, the racew-aysare left unscarred; Moreover,-by applying the tests at this point in theoperations, pieces that are too soft are discovered then and the uselessexpense of finalgrinding obviated. q Since the depths of penetration canbe indicated by the tester it will be seen that it is applicable to thetesting of pieces at considerable'd-istances below their surfaces as,clearly, adepression of suflicient diameter to receive the penetratormay first be made in the piece and the tests made upon the material atthe bottom of such depression.

It will be seen that we have provided a tester which not only isapplicable to the testing of pieces havingfiat surfaces but isalsoapplicable to the testing of pieces having-curved surfaces at andbelow the "curved surfaces, which can be quickly operated and givesaccurate results which is simple in construction and comparativelyinexpensive to manufacture, and yet is so simple in operation that itmay be ut into the hands of,

I and operatedsuccess ully by, any unskilled operator as, for example,the ordinary shop Workman.

' Having thus described our invention, what I "trator, and with meansopposing the flexing of said lever at said joint with ajpredeterminedconstant force, of means automatically controlled b the movement of thepenetrator for indicating the depth of the tit depressionmade by thepenetrator; substantially as described. j

2. In a device of thecharacter indicated, the combination withpenetrator with means'including a jointed leverfor causing thepenetration of the test piece by the penetrator, and with means opposingthe flexing of said lever at saidjoint with a predetermined constantforce, of a device for indicating the depth of the depression made bytheenetrator, and means operatively connect- 1n said device and said firstnamed means; su stantially as described.

3. In a device 01 the character indicated, in combination, a penetrator,force applying mechanism including a jointed lever, the joint of whichis adapted to yield under the application of a predetermined force, forcausing the penetration of the test piece by the penetrator, and meansfor indicating the depth of the depression made by the pene-- trator,such force applying mechanism including means whereby the maximum forceapplied thereby isconstant; substantially as described.

. 4. In a device of the character indicated, in combination, a testindevice, force applying mechanism including a jointed lever, the joint ofwhich is adapted to yield under the application of a predeterminedforce, for causing the dei'ice to operate'upon the test piece, suchmechanism includinga lever to which force is applied, and a compensatingmeans receivin and transmitting force fromthe lever an whereby the ratiobetween the force-effectively applied to the lever and that operativelytransmitted is maintained constant in the various angular positions ofthe lever; substantially as described.

5. In a device of the character indicated, in combination,.-a testingdevice and force applying mechanism for causing the device to operateupon the test piece;.such mechanism including a lever to which force isapplied and a fulcrumed cam-surfaced element for receiving andtransmitting force from said lever, said element having its cam-surfacein connection with said lever and such cam-surface being of a contoursuch that the moment'arms extending from the fulcrum of said element tothe respective points of connection of said cam-surface with said leverso vary in length as to com ensate for the changes in angular position 0the lever;

substantially as described] 6. In a device of the character indicated,in combination, a testin device, force applyin mechanism inclu mg ajointed lever, the jomt of which is adapted to yield under theapplication of predetermined force, for causing the device to operateupon the test piece, such mechanism including a lever to which force isapplied, and means whereby said lever is incapable of applying a forcein excess of a predetermined amount; substantially' as described.

7. In a device of the character indicated, in combination, a testingdevice and force applying mechanism for causing the device to operateupon the test piece; such mechanism including a lever to which force isapplied and one of whose arms comprises two sections-hinged together,and such mechanism also including means for normally holding saidsections rigid and unyielding with respect to each other, saidmeansbeing yieldable so as to fail and permit appreciable movement ofthat section of the arm to which force is applied and under a constantload in excess of a predetermined amount; substantially as described.

8. In a device of the character indicated, in combination, a testingdevice and force applying mechanism for causing the device to' operateupon the-test piece; such mechanism including a lever to which force isapplied and one of whose arms comprises two sections hinged together andcarrying cooperating abutments, and such mechanism also including a loadapplying device 0011- one of said sections, a line attached to the me.

other of said sections at a distance from said hinge and passing oversaid pulley and through the fulcrum of said lever, and a load elementconnected to said line, whereby said load acts to force said abutmentstono gether and prevent :relative movement of said sections at thehinge; substantially as described.

10. In a device of the character indicated, in combination, a testingdevice and force 5 applying mechanism for causing the device to operateupon the test piece; such mechanism including a lever to which force isap: plied and a compensating means receiving 7 and transmittin forcefrom the lever and mo whereby the ratlo between the force applied to thelever and that operatively transmitted is maintained constant in thevarious angular positions of the lever, and such mechanism alsoincluding means whereby said 11%- ing plunger for causing thepenetration of the test piece by the penetrator, and an indicator, of alever fulcrumed adjacent said plunger and having an arm operativelyconnected therewith to be actuated thereb during travel of the plungerand also havln an arm operatively connected with said in ica-' tor tooperate the latter to indicate the amount of movement of the plunger,and

ment in fixed position means connected with said plunger to govern theamount of force applied thereto.

12. In a device of the character indicated, the combination with anabutment for the test piece and a force applier adjacent thereto, saidabutment being shiftable to vary its distance from the force applier topermit the insertion of test pieces of difierent sizes between them, ofmeans for locking the abuting a block carrying the abutment, aresistance piece-adjacent said block, and means abutment, said forfixing the position of the resistance piece and for jamming said blockinto fixed contact with said resistance piece; substantially asdescribed.

13. In a device of the character indicated, the combination with a base,a testing device for the test piece, and a table for. supporting thepiece in testing relation to the testing device, such tablebeing'removable from the base, of means for fixing the table upon thebase; such means comprising a support fixed to the base and having atongueand-groove-joint connection with the table,

and means for wedging said connection; substantially as descrlbe 14:. Ina device of'the character indicated, the combination with a base, anabutment for the test piece, a force applier adjacent thereto, a testingdevice, and a table for supporting. the piecein testing relation to thetesting device the force a abutment being shiftable to vary its distancefrom the force applier to permit the insertion of test pieces ofdifierent sizes between them, and said table being removable from thebase, of means for lockmg the abutment in fixed position and for fixingthe table upon the base; such means comprising a support fixed to thebase and having a tongue-and-groove-'oint connection with the table, ablock ad acent said table and carrying said abutment, and means forwedging sai block in fixed contact with said table to thereby relativelyfix the table and block and to wedge said connection to relatively fixsaid table and support; substantiallyas described. j

15. In a device of the character indicated, in combination, a testingdevice and a table 'for supporting the test piece in testing relation tosaid'device; said table comprising a block, a table plate, adjustingscrews connecting said block and plate whereby adiustment of said screwsvaries the efiective plunger and having such means comprise plier andthe I eeann ing movement of said plunger and also having an arm inconnection with said indicator, whereby the extent of movement of saidplunger is indicated by said indicator, a lever for applying force tosaid plunger to move it, mechanism In connection with said lever forpredetermining the maximum load which can be effectively applied to saidlever, and a fulcrumed compensating cam block disposed between saidplunger and lever and having aportion in connection with said plungerand a cam surface -m connection with. saidlever, the contour of saidsurface being such that the moment arms extending, from the fulcrum ofsaid blockto the respective points of connection off-the lever withsaidzcam surface so vary in length as to compensate for changesinangular pamtion of the lever; substantially as described.

17. Inc,- device of the character indicated, the combination with apenetrator, a jointed lever adaptedito-yield at itsjoint upon theapplication of a predetermined force applied to said lever, anoperative'connection between the penetrator and lever to transmitsaid'predefermined' force to said lever, a register to show the degreeof penetration, and an operative connection between the penetrator andregister.

18. In ajdevice'of the character indicated,

the combination with a penetrator, of a jointed lever adapted to yieldat its joint, a governor to determine the amount of. force tocause saidjoint to yield, and an operative connection between the penetrator andlever to transmitonly said predetermined force to the penetratorlrrespective of the amount of force initially applied "to said lever.

19. In a device of the character indicated,

the combination witha penetrator, of a two part pivotall mounted leveroperatively connected wit the penetrator, there being a pivoted ,jointbetween the parts separate from the pivotal mount of said lever, andmeans for' yieldingly-- .connecting the two parts of said lever topermit the joint to break and continue such breaking movement under theapplication of a constant predetermined force. v

20. In'a device of the character indicated, the ombination'iwith apenetrator,'of one section of a jointedflever, a pivot for said smction,it connection between said section In testimony \vlivroof", we. hereunto:illix 10 and pvnvtrutor on one side of said pivot, 21 our signatures Inthe presence. of two wit- SOCOINI soctlon ul' snnl lover pn'otallyconnvsscs.

nvclml with tho first section on tho opposite MUCH M 'POCRWFI I Hidfl ofsaid )ivot, and means for yiolilingly "will F G F 1 connecting t iotwo'svctions of the lover to [)ll'lllil tho joint to break and vontin'ncWitnesses:

such breaking movement, under tho :ipplica- 'IIJAAM I). \Ymu'mlAN,

tion of a constant predetermined force. HAROLD A. liinusnuny.

